Perfusion chamber and cannulae therefor



Jan. 20,-1970 A. RLAVENDER .a1-A1. :490,438

` PERFUSION CHAMBER A-ND CANNULAE THEREFOR' Filed June e, 196'? 2 sheets-sham 1 l I I l A 00 @H Z 206 l l, .70

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mi '9% l if' I Y l 64 u; 7222-1 Jan. 20, 1970 A. R. LAVENDER ET AL 3,490,438

PERFUSION CHAMBER AND CANNULAE THEREFOR Filed June 8, 1967 2 Sheets-Sheet 2 FEE-2 h j?! iii ,w

j? 1% 19a/f United States Patent O 3,490,438 PERFUSION CHAMBER AND CANNULAE THEREFOR Ards R. Lavender, Arthur A. Berndt, and John J. Stupka,

Chicago, Ill., assignors to the United States of America as represented by the United States Atomic Energy Commission Filed June 8, 1967, Ser. No. 645,572 Int. Cl. A61b 19/00; A61m 1/03 U.S. Cl. 128-1 7 Claims ABSTRACT OF THE DISCLOSURE A kidney perfusion chamber includes a container with lan internal surface free of sharp edges and coated with graphite having absorbed thereon benzalkonium-heparin, and an arterial cannula, a uretal cannula, and a venous cannula each sealingly fitted in an orifice through a wall of the container. The artery and the ureter of a kidney placed in the container are respectively connected to the arterial and uretral cannulae of the chamber. The vein of the kidney is left unconnected and communicates with the venous cannula via the interior of the container. The radial or ulnar artery and the branch medial vein of a patient with an inoperative renal system are respectively connected, via suitable tubing, to the arterial cannula and the venous cannula of the chamber. Blood from the arterial system of the patient ows into the kidney via the arterial cannula and -venous blood from the kidney returns to the patient via the kidney vein, the container, and venous cannula. Urine produced by the kidney is discharged via the kidney ureter and the ureter cannula.

CONTRACTUAL ORIGIN OF THE INVENTION The invention described herein was made in the course of, or under, a contract with the United States Atomic Energy Commission.

BACKGROUND OF THE INVENTION This invention relates to extracorporeal organ perfusion and more particularly to a chamber and associated cannulae for kidney perfusion by blood from chronically cannulated vessels.

When the renal system of a human or other warmblooded animal ceases to function, whether as a result of injury, disease or congenital defect, a substitute must be provided if life is to continue. In general, a substitute is provided in one of two manners, the patients blood supply is passed through an artificial kidney machine which performs the renal function or a human kidney is transplanted into the patient. The artificial kidney machines now in use are functionally sufficient to maintain the health of the person who must rely on them. The problems with the machines are that they are expensive, they require trained personnel in attendance during the entire time of use, their blood capacity is such that transfusions are frequently required when the machine is used and the patient is usually tied to the machine for two periods of six hours each week. The most desirable solution to the problem is a human kidney transplant.

Many kidneys which are transplanted are otbained from cadavers. They must be removed from the cadavers shortly after death and inserted into the renally deficient system in an operation which must be classified as major surgery. It is a fact that about l in kidneys obtained from cadavers are nonviable and a further 20-40% of the viable cadaver kidneys do not function at maximum eiciency immediately after transplant. After the kidney is transplanted, the recipients system begins to manufacture antibodies Which results in rejection of a large percentage of the transplanted kidneys. Rejection as opposed to nonviability may take place anywhere from 3 days after the transplant up to a few years. As a person cannot live for any great length of time without renal function, once a transplanted kidney ceases to function for any of the abovementioned reasons an artificial kidney machine must be employed or -another kidney transplanted. Major surgery is involved, not only in transplanting a kidney into a system, but also in removing a non-functioning kidney. It is obvious that repeated transplants are deleterious to the recipients health.

An object of this invention is to provide means for extracorporeal transplants which mitigate the problems heretofore mentioned.

A number of experiments have been conducted in which a kidney has been excised and perfused extracorporeally. In general, these experiments break down into two categories, open and closed systems. In the open system, the excised kidney is connected to a vascular supply and allowed to function in an open container where ready access is provided for biopsy, blood sampling and the like. In the closed system, the kidney is attached to a vascular supply and housed in a closed container of fixed volume and allowed to operate. Neither system has produced normal renal function for any appreciable time. The perfusion chamber and cannulae of this invention enable the extracorporeal perfusion of a human kidney attached to the vascular supply of a renally deficient human being for a sufiiciently long period of time to determine not only if the kidney is viable but also if an early rejection occurs. In one case a human kidney was perfused extracorporeally A for 2S days, at which time the kidney was rejected due to The invention may be more readily understood by reference to the following drawings in which:

FIG. 1 is a top view partially in section of the perfusion chamber of this invention;

FIG. 2 is a side view of FIG. 1;

FIG. 3 is a sectional view of a ureteral cannula;

FIG. 4 is a sectional view of an artergil cannula;

FIG. 5 is a sectional view of a venous cannula; and

FIG. 6 is a sectional view of a body cannula.

With reference to FIG. 1, perfusion chamber 10 is oval in shape and formed from a one-piece plastic container 12 (see `also FIG. 2) which may suitably be made of methylacrylate or methylmethacrylate resin. Container 12 has a front side wall 14 and a back side wall 16 which have fiat outside surfaces 15 and 17, respectively. Chamber'12 has a bottom 18 which forms rounded corners 20 with side walls 14 Iand 16. Front side Wall 14 contains an arterial orifice 22, a venous orifice 24 and a ureteral orifice 26.

The top of container 12 is formed into lip 28. Lip 28y has a plurality of threaded holes 30 and a continuous circumferential groove 32 located between holes 30 and the inside of container 12. Inside surface 34 of container 12 is entirely coated with graphite having absorbed thereon benzalkonium-heparin (GBH). The interior surface is first etched with sodium and then coated with graphite. Then the graphite is coated with benzalkonium chloride after which there is applied a coating of sodium or potassiurn heparin. The benzalkonium salt reacts with the heparin to form a benzalkouiumheparin complex which firmly adheres to the graphite, This GBH coating or a methylacrylate or methylmethacrylate resin is one of vthe most important features of the perfusion chamber.

Screw holes 36 are located in front side wall 14 and surround each orifice 22, 24 and 26 in the front side wall. Three holes 36 surround each orifice and are spaced at 1Z0-degree intervals. Holes 36 are threaded and extend into, but not through, side wall 14.

Cannulae housings 38 are tubular in shape and have circular cannulae apertures 40 therein and circular flanges 42 therearound. Housings 38 fit through apertures 22 and 26 in front side wall 14. End surfaces 44 of housings 38 are flush with inner surface 34 of container 12. Each flange 42 has a circular groove 46 on the side of the flange which faces outside surface 1S of front side wall 14. Groove 46 is located between the housing wall 48 and three holes 50 spaced at 120-degree intervals extending through flange 42. Housing 38 has a second set of three holes 52 spaced at 120-degree intervals that surround cannula aperture 40. A gasket 54 in each groove 46 seals the interior of container 12 from the outside atmosphere when housings 38 are attached to container 12 by means of screws 56 inserted through holes 50 into screw holes 36.

Referring now to FIG, 3, ureteral cannula l60 is tubularly shaped and has a circular flange 62 and an outer section 64 which extends through cannula housing aperture 40 and an inner section 66 which extends into the interior of container 12. Inside edge y68 of flange 62 is Sculptured and has rounded surfaces 70. The outside edge 72 of ange 62 has three screw holes 74 spaced at 120-degree intervals. Screw holes 74 are threaded and extend part way through flange 62. Cylindrical groove 76 in flange 62 is located outside of screw holes 74. Ureteral cannula 60 has a channel 78 extending therethrougth. Tip 80 of inner section 66 is square-cut and chamfered at a 30- degree angle to a knife edge 82 which is 174000 in thickness. The lumen, that is, the diameter of channel 78, varies with the size of each individual ureter to which cannula 60 is attached but is adjusted so that the wall thickness of inner section 66 is about 0.02, A plurality of circumferential grooves 84 extend from tip 80 of cannula 60 back along the outside of inner section 66. The first of grooves 84 is 0.005 from tip 80. Channel 78 terminates in a threaded chamber 86 in outer section 64. Outer chamber 8'6 may be threaded to receive a Luer female plug.

Ureteral cannula 60 is inserted into housing 38 from the inside of container 12. A gasket (not shown) is inserted into cylindrical groove 76 and the outer section 64 is inserted through cannula aperture 40. Cannula 60 is adjusted until screw holes 74 in ange 62 are aligned with holes 52 in housing 38. Screws (not shown) are then inserted into screw holes 74 and tightened until cannula 60 is securely sealed to housing 38.

With reference to FIG. 4, arterial cannula 90 is tubularly shaped and formed of flange 92, outer section 94 and inner section 96. Inside edge 98 of flange 92 is sculptured and has rounded surfaces 100. The outside edge 102 of flange 92 has three screw holes 104 spaced at 120- degree intervals. Screw holes 104 are threaded and extend part way through flange 92. Cylindrical groove 106 in flange 92 is located outside of screw holes 104. Arterial cannula 90 has a channel 108 extending therethrough. Both tips 110 of inner section 96 and outer section are squarecut and chamfered at a SO-degree angle to knife edges 112 which are 1/1000" in thickness, The lumen of arterial cannula 90, like that of ureteral cannula 60, is variable, depending upon the size of the artery used therewith, but the wall thickness of inner section 96 remains about 0.02. A plurality of circumferential grooves 114 extend from tips 110 of cannula 90 back along the outsides of inner section 96 and outer section 94. The first of grooves 114 in inner section 96 is 0.005" from tip 112. Channel 108 in outer section 94 of arterial cannula 90 is taper-bored to a standard lumen size. The lumen size of channel 108 in outer section 94 and the outside'diameter of outer section 94 are standard for all cannulae, except ureteral cannula 60, which permits the use of uniform diameter tubing regardless of the size blood vessel to Which a cannula is connected.

Arterial cannula 90 is inserted into housing 38 from the inside of container 12. A gasket (not shown) is inserted into cylindrical groove 106 and outer section 94 is inserted through cannula aperture 40 in housing 38. Cannula 90 is adjusted until screw holes 104 in ange 92 are aligned with holes 52 in housing 38. Screws (not shown) are then inserted into screw holes 104 and tightened until cannula is securely sealed to housing 38.

With reference to FIG. 5, venous cannula is tubularly shaped and formed of ange 122, outer section 124 and inner section 126, '[(he inside edge 128 of flange 122 has a cylindrical groove and three holes 132 spaced at 120-degree intervals. Groove 130 is located inside of holes 132. Venous cannula 120 has channel 134 extending from tip 136 in outer section 124 through outer section 124 and most of inner section 126. Channel 134 terminates near end 138 of inner section 126. Three side ports 140 near end 138 in inner section 126 connect with channel 134. External corners 142 of inner section 126 are rounded. All internal corners 144 in inner section 126 formed by -ports 140 are also rounded. Tip 136 in outer section 124 is square-cut and chamfered at a 30-degree angle to a knife edge 146 which is 1/1000 in thickness. A plurality of circumferential grooves 148 eX- tend from tip 136 of cannula 120 back along the outside of outer section 124. The lumen of channel 134 of venous cannula 120 and the outside diameter of outer section 124 are sized to fit standard tubing.

Venous cannula 120, unlike ureteral cannula 60 and arterial cannula 90, is inserted into container 12 from the outside. Inside section 126 is inserted through venous orifice 24 in front side wall 14 of container 12, A gasket (not shown) inserted into cylindrical groove 130 seals the inside of container 12 once screws 56 have been inserted through holes 132 into screw holes 36 in front side wall 14 and tightened.

With reference to FIG. 6, body cannula 154 is formed of outer section 156 and inner section 158. A channel 160 extends therethrough and tips 162 are square-cut and chamfered at a 30-degree angle to knife edges 164 which are 1A000 in thickness. A plurality of circumferential grooves 166 extend backward along the outside of inner section 158 and outer section 156 from tips 162. The rst of grooves 166 is 0.005" from tips 162 of cannula 154. Both the lumen size and outside diameter of outer section 156 are the same as in arterial cannula 90 and venous cannula 120 so that uniform tubing may be used throughout.

With reference to FIG. 1, body cannulae 154 are attached to an arterial supply (not shown) and a venous system (not shown). The outer section 156 of cannula 154 attached to the arterial supply is inserted into tubing 170 which is, in turn, connected to outer section 94 of arterial cannula 90. Tubing 170 is secured to outer section 94 of arterial cannula 90 by ligatures (not shown) which correspond to cylindrical grooves 114 in outer section 94 of arterial cannula 90. Similarly, tubing 170 is secured to outer section 156 of body cannula 154 by ligatures. However, to insure that tubing 170 does not slip from body cannula 154, a split tube 172 with circumferential grooves 174 therein surrounds tubing-'170 and outer section 156 of body cannula 154. Split tube 172 is secured by ligatures. Similarly, tubing 170 connects outer section 124 of venous cannula 120 to outer section 156 of body cannula 154 leading to the Venous system. Tubing 170 is secured to outer section 124of venous cannula 120 in the same manner as described above and a split tube 172 is also employed to secure tubing 170 to the body cannula 154 leading to the venous system. All body cannulae 154 are internally coated with GBH. Tubing 170 may be silicone rubber or a suitable plastic which is internally coated with GBH.

A kidney with an artery 182, a vein 184 and a ureter 186 is placed in container 12 and connected as follows. Artery 182 is connected to inner section 96 of arterial cannula 90 and secure by ligatures. Ureter 186 is connected in a similar manner to inner section 66 of ureteral cannula 60. Vein 184 is not directly connected to venous cannula 120 but opens to container 12 so that venous blood from kidney 180 will bathe the kidney and till chamber 10.

With reference to FIG. 2, a plastic top 190 which may be the same material as container 12, is formed to tit over lip 28 of container 12. Top 190 has a plurality of threaded holes 192 which correspond to threaded holes 30 in lip 28 of container 12. Screws 194 in threaded holes 192 and 30 fasten top 190 to container 12. A gasket (not shown) in groove 32 provides a seal between top 190 and container 12. Inside surface 196 of top 190 may be partially coated with a silicone grease which is transparent to enable kidney 180 to be viewed. The balance of inside surface 196 is coated with GBH. Top 190 has three ports 198. Two ports 198 contain removable plugs 200. A nonremovable plug 202 in the third port 198 consists of a housing 204 and a center section 206 of silicone rubber. Plug 202 is securely fastened to top 190 by screws (not shown). Plugs 200 and 202 are machined to precisely it into ports 198 so that inner surface 196 of top 190 is smooth.

In operation, a kidney is obtained from a cadaver or donor by an operative technique which will be explained later. Kidney 180 is put into container 12 and artery 182 and ureter 186 are connected as hereinbefore described. A body cannula 154 is inserted into the radial or ulnar artery of a patient with an inoperative renal system. Cannula 154 is then connected to arterial cannula 90 by the method hereinbefore described. Similarly, a second body cannula 154 is inserted into the branch medial basilic vein and connected to venous cannula 120 as hereinbefore described. A clamp (not shown) on tubing 170 leading from the radial artery is slowly opened until blood ows from the patient into kidney 180 A clamp (not shown) on renal vein 184 is removed after blood ows into kidney 180. After vein 184 has been freed, top 190 is secured to container 12 as described and blood owing from vein 184 lls container 12. Blood is prevented from exiting container 12 by a clamp on tubing 170 leading from venous cannula 120. Air in container 12 is removed by allowing blood to ow through a needle (not shown) inserted through plug 202. After all the air has been removed from container 12, the needle is removed, the clamp on the tubing 170 connected to venous cannula 120 is also removed and perfusion charnber is ready for operation. At this time, kidney 180 is functionally in the vascular system of the patient. Blood from the arterial system of the patient flows into kidney 180 and venous blood from the kidney returns to the patient. Urine produced by kidney 180 is discharged from chamber 10 through ureter 186 connected to ureteral cannula 60.

Perfusion chamber 10 is adaptable for research in that kidney 180 may be viewed through top 190, and blood specimens and tissue biopsy may be obtained through center section 206 in plug 202. If for any reason kidney 180 fails to function at proper efficiency or is rejected, an artificial kidney machine can be connected to chamber 10 through ports 198 by removing plugs 200 therefrom. In this manner new vessels do not have to be cannulated.

As mentioned before, perfusion chamber 10 has been utilized to keep a human kidney alive and in good functioning order for 25 days while attached to a human vascular system. This chamber has worked where other chambers and methods have failed. Features which seem to be important for its successful operation follow. Container 12 was machined from a single piece of an acrylate or methacrylate resin, such as methylacrylate or methyl methylacrylate, all internal surfaces were coated with GBH and as many internal projections and corners as possible were rounded. When visual inspection is necessary, a portion of the chamber, such as the cover, is coated with silicone grease which gives transparency and some protection from blood clotting, although the GBH coating is preferable for this purpose. Blood clotting has been found to be the major problem, and this has been overcome by our invention of a suitably coated perfusion chamber substantially free of sharp comers.

Another important aspect of our invention is the special design of the cannulae -used with the perfusion chamber. As mentioned before, inner sections of the cannulae have thin walls, about 0.02" in thickness, and in all cases the largest possible cannulae were used. The larger the lumen size the greater the blood flow to the kidney and the lower the blood turbulence. Minimum blood turbulence is important because turbulence causes clotting and hemolysis. The square-cut edges of the cannulae tips prevent traumatization of the blood vessels when the cannulae are inserted. Cannulae previously available all have beveled openings which, when inserted into a vessel, gouge the vessel wall. The trauma resulting therefrom may lead to infection or blood clots which break off into the blood stream. A point common to all cannulae is the distance between the cannulae tips and the first of the circumferential grooves in the cannulae. This permits ligation of the blood vessel attached thereto near the tip of the cannula. In most cannulae the ligature is applied at a point distant from the tip of the cannula, which allows blood to ilow between the cannula and the vessel wall. This blood collects and results in the distention of the vessel, thereby weakening it and forming clots in the dead l space. These clots build up and eventually break off into the blood stream. The chamfered knife edges of the cannula aid in preventing the formation of blood clots and also permit the largest pos-sible cannula to be inserted into each Vessel.

The cannula flanges and seals were also carefully designed. The inside edge of each cannula llange was formed so as to remove as many sharp corners as possible from the blood llow path. Gaskets are placed outside of screw holes in the arterial cannula and the ureteral cannula 60, whereas the gasket ts inside of holes 132 in venous cannula 120. The placement of gaskets enables chamber 10 to be isolated from outside bacteria and other materials that could possibly be harmful to kidney 180 contained therein. So, also, screws 194 are outside the gasket that seals top 190 to lip 28 of container 12. And, as mentioned before, silicone rubber center section 206 of plug 202 permits blood samples or biopsy of kidney tissue to be taken without opening perfusion chamber 10 to outside undesirable influences.

Still other features of chamber y10 are the cannula housings 38 which permit the use of a smaller chamber volume, because cannulae do not extend into the chamber and take up space. Renal vein 184 s not directly connected to the venous cannula so that venous pressure is not built up to impair blood ow and hinder kidney function. Since venous outflow is not restricted, kidney is free to expand and contract in response to the patients pulse in the same manner as it would if it were in the patients body. Also, the absence of increased pressure in and around the kidney allows lymph to drain from the kidney as it is produced. If the lymph were t-o be retained in the kidney then eventually tissue would be destroyed and the kidney would cease to function.

Each of the novel features, not only of the chamber but also the cannulae, contribute to the viability of the kidney and it is difficult to tell which is the most important; the combination of all `features working together gives a device which accomplishes successful perfusion which hitherto has not been done with other devices.

Before the final design of perfusion chamber 10 was determined 75 experiments were uonducted. The operative techniques employed in those experiments involving dogs and sample data obtained therefrom are presented below.

The perfusion chamber employed in the dog experiments was similar to, but not identical with, that hereinbefore. All cannulae were machined from a polymer of triuorochloroethylene and coated with GBH. The body cannulae employed were identical to those decsribed above and all gaskets were silicone rubber. The tubing was initially polyvinyl internally coated with GBH, but silicone rubber with a smooth internal surface was found to be more satisfactory.

Healthy mongrel dogs 20-25 kg. in body weight were anesthetized with intravenous pentobarbital. An isomotic saline solution containing creatinine, p-amino-hippuratc (PAH), glucose, penicillin and streptomycin was infused into the jugular vein at 1.0 ml./min. by a constant-speed pump. Plasma creatinine values were maintained at 7-9 mg. percent and plasma PAH at 2 mg. percent. A total of 7 grams of glucose, 1.0 gram of streptomycin and 1 million units of crystalline penicillin were infused per day. A kidney was excised in the following manner.

The right femoral artery was cannulated for blood sampling and for blood pressure monitoring by a mercury manometer. Both ureters, exposed by a loweraabdominal, mid-line excision, were cannulated with polyethylene catheters. The largest cannulae possible were inserted into the left femoral artery and vein. In the majority of experiments, the arterial cannula size was 0.17 to 0.19" LD., and the Venous cannula size was 0.19 to 0.21 LD. Each cannula was attached to a 10.0 length of a 0.25 I.D. tubing, either GBH-coated polyvinyl or silicone rubber. The tubes were lled with heparinized saline and the free ends were closed With screw clamps. A large branch each of the femoral artery and vein was isolated proximal to the tip of each cannula when regional heparinization was used (dogs 10 to 28). Polyethylene tubing was inserted into these arterial and venous branches and connected to syringes in a constant-speed pump. The arterial syringe contained heparin, 1000 units/ml., and the venous syringe contained protamine sulphate, 10.0 mg./ml. The pump rate was 1.5 or 3.0 1111./ hr.

After closing all wounds, the animal was turned onto its right side and the left kidney was exposed by a retroperitoneal ank approach. The ureter and kidney were freed of all nonvascular attachments and the ureter Was severed at the pelvic brim. Mannitol, 50 rnl. yof a 25% solution, was then given intranvenously. When diuresis was established and the kidney was swollen, both the renal artery and vein were clamped simultaneously near the hilum. Both vessels were ligated at their origins, the vessels were severed distal to the ligatures and the kidney was removed. The cut end of the renal vein was ligated and the vessel clamp was removed. The venous ligature prevented decompression of the kidney during the cannulation procedure.

The largest cannula possible was inserted into the renal artery and tied into position. In most experiments, the cannula size was 0.17 to 0.19 I.D. After tying in the ureteral cannula, the kidney was placed in the perfusion chamber and all cannulae were seated and sealed in the chamber wall. Isosmotic saline at 38 C. was used to lill the chamber. Femoral artery and vein tubes were attached to the appropriate cannulae from the perfusion chamber. The arterial tubes clamp was loosened until blood appeared distal to the clamp. `The renal vein ligature then was removed. The chamber top was sealed and air was displaced through the stopcock by renal venous outow. When all air had been evacuated, the stopcock was closed and the venous tubes clamp was removed. The arterial tubes clamp then was opened gradually over a period of about one minute. Blood immediately displaced saline in the chamber, the kidney pulsated and urine appeared Within 1/2 to 2 minutes.

Urine collection periods of two hours each were begun when urine ow from each kidney stabilized, usually Within two hours of the start of perfusion. Blood samples were drawn at the midpoint of each collection period. All urine and blood specimens were analyzed for creatinine, PAH, sodium and potassium. Creatinine and PAH clearances were used to estimate glomerular iiltration rate (GFR) and renal plasma flow (RPF), respectively. Some, but not all, urine specimens were tested for pH, glucose and protein. Each experiment continued until the animal died, usually from hemorrhage or respiratory failure, or until the perfused kidney showed functional deterioration. At the conclusion of an experiment, the perfused kidney was inspected for signs of ureteral 0bstruction, arterial occlusionvand infraction. In l1 experiments, both kidneys were weighed and sectioned for histologic study.

The technical features of these experiments are shown in Table I. Means excision time was 13.9 minutes with a range of 5.3 to 22.0 minutes. Mean perfusion time was 33.2 hours with a range of 8.0 to 73.0 hours. Perfusion time was 24 hours or longer in 18 experiments. In half of these, perfusion time was 48 hours or longer. In 11 experiments in which kidney Weights were obtained, weight of the perfused kidney did not differ significantly from weight of the in situ kidney. With the exception of dog number 8, plasma hemoglobin did not rise significantly. Most of the experiments were terminated by death of the donor animal but several were complicated by clotting towards the end of the experiment.

TABLE I.EXTRACORPOREAL PERFUSION OF DOG KIDNEY Kidney Weight Blood Pressure Plasma Hb Excision Perfusion (gms.) (mm. Hg) (mm. percent) Time me Reason for (min.) (hrs.) Perf used Control Initial Final Initial Final Termination Complications 7.0 135 20 Hemorrhage Tubing clot. 7. 8 90 60 .do Venous occlusion. 5. 3 150 80 Respiratory failure- Tubing clot. 7. 5 110 118 do Do. 13. 5 100 120 3.4 3. 9 Sacriiiced.. Arterial clot. 22. 0 136 40 3. 9 1. 9 Embolus 16. 4 120 76 0. 7 0.3 Hemorrhage.. 11. 3 130 110 44. 4 69. 6 sacrificed- Kinked ureter. 16.8 75 0. 6 0. 3 Hemorrhage.. Tubing clot. 14. 1 114 68 1. 0 0. 9 Respiratory fa ur Hemorrhage. 18. 3 150 66 1.3 1. 7 do Tubing clots. 13. 8 124 60 0. 1 1. 9 Hemorrhage Do. 13.3 130 41 4.2 6.4 0 15. 1 118 88 0.3 0.8 Sacriced. 18. 3 120 94 0. 3 0. 3 do Kinked ureter. 17. 3 124 60 5. 2 5. 9 do Tubing clot. 14. 8 128 78 1. 1 0. 9 Respiratory failure. Kinked ureter. 21. 8 120 40 6. 0 3. 5 sacrificed- Hemorrhage. 22. 0 120 90 0. 7 3. 6 0.---.." Tubing clot. 13. 5 140 40 9. 9 2. 0 Respiratory fa ure 13. 0 100 60 3. 6 2. 5 Hemorrhage.. Do. 13.9 110 58 3.8 1.3 do 12. 9 100 34 1. 4 0. 6 Respiratory failure 9. 0 110 80 0.8 0. 4 Hemorrhage 12.1 30 4. 6 5.0 .do Venous occlusion. l1. 8 140 110 0. 8 1. 5 sacrificed-- 14. 1 2 116 80 1. 4 6. 0 do Hemorrhage 12. 1 2 110 44 0. 4 3. 0 Hemorrhage Tubing clots.

Mean 13.9 71. 0 68.3 4. 2 5. 2

TABLE II.-HISTOPATHOLOGY Ol?` PERFUSED KIDNEYS Number with Lesion In Situ Lesion Perfused Interstitial Nephritis 6 Tubular Degeneration Tubular Necrosis Tubular Dilation.

O Dimm@ Necrosis 5 Table III summarizes functional data for all 28 experients. The ratio, perfused to in situ kidney, was calculated for each function in each period for each experiment. The means ratio of each function was then calculated for each experiment. The means for each dog is shown. Although there was individual variation, mean ratios of GFR and RPF for the series approximated unity. Excretion of water, sodium and potassium was generally higher in the preferred than in the in situ kidney. In 13 experiments, GFR and RPF in the perfused kidney were 90 percent or more of the values in the in situ kidney. They were at least 60 percent in 7 additional experiments.

Neither proteinuria for glycosuria was observed. Urine pH of the two kidneys was the same, usually 7.0 to 7.4. Hemoglobinuria did not occur. Hematuria occasionally appeared in one or both kidneys.

Mean 9 2. 5 1. 3

Each ratio shown is the mean of the ratios obtained in each collection period of each experiment.

FF=f1ltration fraction.

The `above experiments were conducted prior to use of perfusion chamber 10 with a human, and the operative technique developed in excising the dog kidneys was applied to the human kidney. Although chamber `10 was designed for renal perfusion it should be suitable for perfusion of :any organ with a solitary arterial blood supply. The principle of free lymphatic and venous drain- :age into container 12 should be of value in perfusion or organs such as ithe pancreas and liver.

It will be understood that the invention is not to be limited to the details given herein but that it may be modified within the scope of the appended claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

'1. A perfusion chamber, comprising:

a container having side walls and a bottom which aret rounded so as to be free of any internal corners, said container having first, second and third orilices therein, the interior of said container being coated with graphite having absorbed thereon benzalkonium-heparin;

a top for said container removably sealed thereto, said top having the surface internal to said `container `coated with a silicone grease or graphite having benzalkonium-hep arin absorbed thereon;

`iirst .and second housings sealingly iitted to said ii-rst and second oriiices, respectivley, in said container and having an internal end ush with the internal wall of said container at the point where each housin-g fits into said container, each housing containing an aperture adapted to receive a cannula, said housings having a surface internal to the container coated with graphite having absorbed thereon, benzalkoni-um-heparin;

a first cannula extending through said aperture in said first housing and sealed to said housing, part of said( cannula being inside said chamber and part of said cannula being outside said chamber; second cannula extending through said aperture in said second housing and sealed to said housing, part of said cannula being inside said chamber and part of said cannula being outside said chamber; and

a third cannula extending through said third orifice in said container and sealed to said container, part of -said cannula being inside said chamber and part of said cannula being outside said chamber.

2. The perfusion chamber of claim 1 wherein the cannulae are coated with graphite having absorbed thereon benzalkonium-heparinf 3. The perfusion chamber of claim 2 wherein the con* tainer and top are acrylate resins.

4. The perfusion chamber of claim 2 wherein the cOntainer and top are methyl methacrylate and the can-l nulae are a polymer of trifluorochloroethylene.

5. The perfusion chamber of claim 1 wherein the first cannula is tubular in shape having: a flange therearound, square-cut ends with chamfered edges, a plurality of circumferential grooves therearound and at least a part of said cannula having thin walls, said ange being l0- cated inside said iirst housing and having 1a side of said iiange facing the interior of said container Sculptured so as to be free of any sharp corners.

6. The perfusion chamber of claim 1 wherein the vthird cannula is tubular in shape having a liange therearound, the part of said cannula outside of said chamber having: a square-cut end with a chamfered edge, a plurality of grooves therearound and thin walls, said flange being located outside said third orifice but in sealing relationship thereto, the part of said cannula inside said chamber having a closed end and a plurality of side ports therein.

7. The perfusion chamber of claim 1 wherein the second cannula is tubular in shape having a flange therearound, the part of said cannula inside said chamber having a square-cut end with a chamfered edge, la plurality of grooves therearound and thin walls, said flange being located inside said second housing and having 'a 1 1 1 2 side of said ange facing the interior of said container Couch et zal.: Surg., October 1955, Iv01. 44, #4, pp. Sculptured so as to be free of any sharp corners. A66g 69 Rosenfeld etal.: Amer. Jo. Physiology, vol. 196, #5,

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